In the manufacture of photosensitive products such as photographic film, paper or the like, it is well known to provide a film with latent images of characters, numerals, symbols, marks the like which are later photographically developed during the processing of the exposed film, for providing information marks such as the manufacturer's name, the date, the film type, frame numbers, frame size and the like along the longitudinal sides or margins of the film. One way of so marking a film, which is generally called side printing, is to optically form light images of characters on the film at the longitudinal margins adjacent each picture frame during the film manufacture, the film being thereby produced with latent images of characters, which characters are later photographically developed during the processing of the exposed film.
Apparatus for producing a film with such latent images of characters as aforementioned, which is generally called side printing apparatus, are well known. Such apparatus are divided into four types in accordance with the forms of the light providing mechanism. One form is a projection mechanism in which a character pattern plate and a light source for illuminating the pattern plate are used to form light images of characters. Another form is a light emitting diode (LED) matrix array in which a plurality of LEDs are selectively energized to form light images of characters. A third form is a liquid crystal display device in combination with light source. A fourth form is a cathode ray tube (CRT) display device.
Such side printing apparatus can be constructed so that the light images are formed in synchronism with the motion of the film in a forward direction by detecting the moved length of the film so as to provide latent images in the film at predetermined positions, and the interval for which the light image forming device is maintained energized is varied according to changes in the speed of motion of the film for the purpose of producing positive images of characters of uniform density.
An example of an apparatus to provide latent images containing information regarding film type and frame number on unexposed photographic film is U.S. Pat. No. 4,965,628, Oliver et al, Photographic Film with Latent Image Multi-Field Bar Code and Eye-Readable Symbols, (Eastman Kodak Company), discloses a multi-field latent image bar code photographically recorded every half frame of a strip of photographic film. One of the fields represents information pertaining to the film and another of the fields represent the half-frame number. Also, U.S. Pat. No. 5,179,266, Imamura, Photographic Film and Method of Identifying Frame Numbers of Photographic Film, and U.S. Pat. No. 5,336,873, Photographic Film Having Frame Number Bar Codes, (both Fuji Photo Film Co., Ltd.), disclose a photographic film provided with bar codes indicating frame numbers attached to respective frames.
Such latent images containing film and frame information are optically printed aside the respective exposable frames of negative photographic film during manufacturing of the film. Such information may be contained in bar codes or other machine readable format. Apparatus capable of printing latent images on unexposed photographic film can use several different techniques to provide the latent image.
Conventional apparatus to perform this function use a "chrome on glass pattern plate" which is then illuminated by a light source for an appropriate exposure period based upon the speed of the film and other factors. While such a system provides excellent quality, the fixed nature of the "pattern plate" makes changing the desired pattern to be imaged, e.g., changing between film types and sizes, a cumbersome process. Type 135 film (thirty-five millimeter width) typically contains individual frame numbers, some of which are represented in bar code format. Further, with the advent of including frame number information in the latent information printed on the unexposed light sensitive film, the "pattern plate" would have be changed every frame of the strip of film. This makes this method impractical.
Another technique is to use a plastic photo-sensitive material to make a plastic mask which is the length of the exposure wrapped around a vertical drum having a circumference at least equal to the length of one piece of film. A light source in the center of the drum exposes the film to the information contained on the plastic mask as the drum rotates and the film moves horizontally. Unfortunately, the plastic mask deteriorates rapidly and produces a relatively poor image quality. Not only must the entire mask must be changed when the desired pattern to be imaged changes but the drum might need to be changed (different circumference) or the drum's mechanical drive system may have to change for different film lengths.
Other apparatus attempt to solve this problem by providing a more changeable method for forming the information to be latent printing on the unexposed light sensitive film. An example is U.S. Pat. No. 4,548,492, Kanaoka et al, Side Printing Apparatus, (Fuji Photo Film Co., Ltd.), which discloses a side printing apparatus which provides latent images of characters, numerals, symbols and the like on a continuously moving film. Such latent images are then later developed. The light images may be formed by (1) projection from a character plate, (2) a light emitting diode array, (3) liquid crystal display in conjunction with a light source, and (4) cathode ray tube (CRT) display device. The apparatus shuts the imaging system off during reverse movement of the film in order to prevent double exposures.
Examples of such apparatus that utilize light emitting diodes and light emitting diode arrays are U.S. Pat. No. 5,274,396, U.S. Pat. No. 4,806,965, and U.S. Pat. No. 5,307,108.
U.S. Pat. No. 5,274,396, Shimoda et al, Bar Code Printing Apparatus, discloses a bar code printing apparatus which uses an LED driver (27) for selectively lighting an LED array (28) in accordance with print pattern data. Light emanating from each LED array is transmitted by way of a flexible light guide (31) in the form of a large, bulky and expensive fiber bundle comprising a considerably great number of optical fibers toward the film. The light in the form of a small dot from the light guide is focused on a margin of the film so as to create a latent image of a small dot. An LED driver (27) selectively lights the LED array to form a light pattern of a numeral or a bar code of the film traveling at a constant speed. This technique provides overlapping areas which will have more exposure than others preventing a homogeneous exposure.
U.S. Pat. No. 4,806,965, Yamanouchi et al, and U.S. Pat. No. 4,884,095, Yamanouchi et al, both entitled Apparatus for Writing Data Onto Photosensitive Film, (Konica Corporation), disclose an apparatus for optically writing data onto non-exposed film coated with photosensitive material while moving the film in a predetermined direction. The data can represent film frame number. The apparatus uses two groups of multi-color light emitting diodes being arranged with a pitch in parallel two lines beings crossing at right angles to a film processing direction. Two columns of light emitting diodes are used with the second column shifted down by half a pixel allowing the second column of light emitting diodes to fill in the gap between pixels of the first column of light emitting diodes. This technique, also used by dot matrix printers, also provides overlapping areas which will have more exposure than others preventing a homogeneous exposure.
U.S. Pat. No. 5,307,108, Yamanouchi et al, Film Data Exposure Device, (Konica Corporation), discloses an apparatus for forming a latent image of an identification data in an edge portion of a new photosensitive film. The apparatus uses light sources LEDs (25) which is sent by an optical fiber (23) via optical fiber head (28) an lens (29) to form an image on the film. Alternatively, the apparatus uses a light source (204) and a lens (205) to expose the film.
Light guides are also used in U.S. Pat. No. 4,544,259, Kanaoka et al, Side Printing Apparatus, (Fuji Photo Film Co., Ltd.), which discloses a printing apparatus for printing a colored mark in a colored dot pattern seven pixels high using light emitting diodes on a colored light sensitive material which is moving. Light guides are used to guide light from a plurality light sections, each light section being illuminated by a plurality of light sources of different colors.
Systems using light emitting diode arrays are relatively slow due to the period of time that it takes for the light emitting diodes to change state and due to the amount of light produced. Exposure time is important in a manufacturing process such as this because the exposure time may limit the speed at which the film can be processed during manufacture. The longer the exposure time, the slower the film must be processed to avoid blurring. These devices are also cumbersome, complex and expensive due to the necessity of having coherent fiber bundles to channel light from the light emitting diodes to the film being exposed. Images formed with fiber bundles typically depend on a precision mechanical drive system to keep film motion constant. If the film wavers during imaging, then the resulting image will be wavy.
Several apparatus are known which can read such frame-identifying indicia during the making of a photographic print from a developed strip of photographic film.
An example of such a bar code reading apparatus is disclosed in European Patent Application No. 0 331 049, Saeki et al, in the name of Fuji Photo Film Co., Ltd. Saeki et al discloses an apparatus for reading bar code of photographic film. Two bar code sensors (8, 9) are disposed at opposite sides of a passage of a photographic film (2), each bar code sensor having first and second photosensor arrays. These photosensor arrays are disposed so as to be located at the passages of the clock track and the data track, respectively, along the line perpendicular to the transportation direction of the photographic film. The DX bar code data (5) and the frame number bar code data (4) are automatically discriminated (read) based on the bar code data configuration read out with the bar code sensor units.
Another example of such a bar code reading apparatus is disclosed in U.S. Pat. No. 5,128,519, Tokuda, Method for Detecting and Positioning Frame Numbers in a Photographic Film, discloses a method of identifying frame numbers of photographic film having both decimal numbers and bar codes both representative of serial frame numbers. When a sensor reads a bar code, measurement of the advanced length of a photographic film is started to obtain a distance of either the bar code or the decimal number relative to the sensor. After the positioning of a frame to be printed in a film framing mask at the printing station, a frame number represented by a decimal number or bar code whose moved distance is within a predetermined range of distances is drawn, thereby identifying the picture frame in the framing mask to have the drawn frame number. FIG. 3 discloses a photographic printer which reads bar code information from color negative film (2) which is indicative of the frame number of the negative to be printed. An illumination lamp (10) passes, optionally, through color filters (11, 12 or 13), through a mixing box (14) before passing through color negative film (2). The light is focused in printing lens (36) on a color photographic paper (37) under control of shutter (39).
U.S. Pat. No. 4,918,484, Ujiie et al, Picture Frame Number Discriminating Method and Apparatus Therefor, (Fuji Photo Film Co., Ltd.), discloses a method and apparatus which discriminates (reads) numerical frame numbers and corresponding coded frame numbers and determines the measurement between the center of the film frame mask and the read frame number.
U.S. Pat. No. 5,390,000, Tanibata, Exposure Apparatus Including PLZT Optical Shutter, (Noritsu Koki Co., Ltd.), also discloses an exposure apparatus used during the processing of exposed negative film in order to print an image contained in the negative film. In so doing, it is preferable to be able to print information regarding the image adjacent the print being made. The apparatus achieves 100% light shielding from the information being printed when closing a PLZT optical shutter even if a light source associated with such information remains turned on.
While these apparatus read bar code, or other machine readable indicia, from a strip of developed photographic film, these apparatus also may print an indicia, usually human readable, in association with a photographic print made from the photographic film, typically a negative film. Typically, this indicia is printed either adjacent to the image on the front of the photographic print or on the reverse side of the photographic print. However, the task of printing frame indicia on prints from developed negative film, whether human readable or machine readable, (which typically utilizes latent image bar code information) is a fundamentally much different problem than the problem of printing a latent image identifying the frame number of the unexposed photographic film during manufacture.
In contrast, U.S. Pat. No. 5,294,950, DuVall et al, (Photo Control Corporation), discloses a system for solving an entirely different problem. DuVall et al discloses an automated film encoding and decoding system for bringing photographic film from the state of exposure to subject matter through all of the processes required to produce finished photos and package the same. The system includes an encoder operative with a camera for the placement of a human and machine readable code on the film at the time of exposure of the film including film frame identification, subject matter information and registration mark information. A decoder is capable of reading the code for the control of production processing equipment in laboratories provided with such equipment.
Since the film frame identification information is printed at the same time as exposure of the remainder of the associated film frame. Since a substantial period of time, usually several seconds or longer, occurs between exposures, a very slow imaging system can be used. Light emitting diodes and liquid crystal displays are entirely adequate for this purpose but are wholly inadequate for exposuring photographic film with high quality latent images during manufacture. Further, liquid crystal displays do not provide a degree of contrast high enough to be suitable for the printing of latent imaging frame identification data during the manufacture of photographic film. Since latent images fade with time, a low contrast bar code at the time of manufacture will deteriorate enough that when the film is eventually developed the bar code could be out of ANSI specification and be unreadable by a bar code reader. Therefore, systems designed with liquid crystal displays would result in an extremely slow system having poor quality.